MOSCOW — The war in eastern Ukraine, which has been on a low simmer for months, drawing little international attention, has escalated sharply in recent days, according to statements Tuesday from the Ukrainian and Russian governments.
In the most lethal fighting so far this year, four Ukrainian soldiers were killed and another was seriously wounded in a battle against Russian-backed separatists in the Donetsk Region of eastern Ukraine, the country’s military said.
The exchange of artillery and machine-gun fire was unusual in that it lasted most of a day. Fighting across the so-called Line of Contact, an about 250-mile-long barricade of trenches and fortifications, are typically briefer.
But it was not the only sign of tensions in a region where Ukrainian and the Russian-backed separatist forces have settled into trenches that have barely moved over the seven years since fighting first erupted in 2014.
European monitors have spotted new weaponry on the Russian-backed side in recent weeks. Artillery fire has become more frequent. And Russian negotiators have warned of a breakdown in peace talks that have been dragging on for years.
On Tuesday, the Kremlin spokesman, Dmitri S. Peskov, acknowledged the recent uptick in fighting and said that Russia “sincerely hoped” it would not escalate. The fighting, he said, was “canceling out the modest achievements made earlier.”
In Ukraine, Parliament on Tuesday approved a statement declaring an “escalation” along the front, essentially acknowledging that a cease-fire negotiated in July had broken down. The statement noted a “significant increase in shelling and armed provocations by the armed forces of the Russian Federation.”
The statement called for Western governments to “continue and increase international political and economic pressure on Russia,” something Ukraine has been requesting for years. The United States and European allies have imposed financial sanctions on Russia, targeting President Vladimir V. Putin’s inner circle, banks and oil companies.
The war that began in 2014 after pro-Western street protesters ousted a Russian-aligned president in Ukraine, prompting a military response by Russia, is the only active conflict in Europe today.
Russia supports the separatists with sophisticated weaponry, ammunition and soldiers, according to Western governments, but Moscow has denied doing so. Despite the static state of the war, the Line of Contact remains a potential flash point for Russia’s relations with the West — and a possible early foreign policy challenge for the Biden administration if things heat up.
Because it divides villages and towns in eastern Ukraine by East-West politics rather than any significant ethnic or sectarian divide, the Line of Contact is sometimes called a new Berlin Wall in Eastern Europe.
Representatives of Ukraine, Russia and the Organization for Security and Cooperation in Europe negotiated the cease-fire in July, one that has held longer than dozens of others that have been made over the past seven years. Eight cease-fires have broken down since 2018 alone.
Tensions between Russia and Ukraine have also escalated along the de facto border between the two countries at the isthmus of the Crimean Peninsula, which is to the south and west of the Line of Contact, and which was annexed by Russian forces in 2014.
In February, the Russian military announced rehearsals of paratrooper drops in Crimea that commentators in Russia and Ukraine saw as possibly telegraphing a fresh Russian incursion. The target this time: water canals supplying Crimea from the Dnieper River in Ukraine.
Ukraine cut off the supply of water from the river when Russia annexed the peninsula. Since then, water has been so scarce that a majority of residents in Crimea do not have round-the-clock supplies, according to the Interfax news agency. Most towns ration supplies by turning off water mains except for brief windows in the mornings and evenings.
The Russian military described the exercise with 3,000 paratroopers as practicing “seizure of the enemies’ objects with subsequent defense until uniting with the main force.” It did not mention water canals. The exercise also practiced marine landings by the Black Sea Fleet.
In response, the Ukrainian military announced an exercise rehearsing the defense of the flatlands between Crimea and the river against air or sea attacks, further ratcheting up tensions.
Maria Varenikova contributed research.